import java.sql.*;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        m5();
    }

    private static void m1() {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;

        //jdbc步骤
        //1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection = DriverManager.getConnection(url, "root", "root");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            //3.写sql
            String sql = "select * from user";

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);

            //5.执行sql
            resultSet = preparedStatement.executeQuery();

            //6.遍历结果
            while(resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println(id+"----"+name+"----"+pass);
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {
                if(resultSet != null) {
                    resultSet.close();
                }
                if(preparedStatement != null) {
                    preparedStatement.close();
                }
                if(connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private static void m2() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入用户名：");
        String name = scanner.nextLine();
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;

        //jdbc步骤
        //1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection = DriverManager.getConnection(url, "root", "root");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            //3.写sql
            String sql = "select * from user where name like ?";

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setString(1,"%"+name+"%");

            //5.执行sql
            resultSet = preparedStatement.executeQuery();

            //6.遍历结果
            while(resultSet.next()) {
                int id = resultSet.getInt(1);
                String username = resultSet.getString(2);
                String pass = resultSet.getString("pass");
                System.out.println(id+"----"+name+"----"+pass);
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {
                if(resultSet != null) {
                    resultSet.close();
                }
                if(preparedStatement != null) {
                    preparedStatement.close();
                }
                if(connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private static void m3() {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
        String user="root";
        String password="root";

        //jdbc步骤
        //1.加载驱动w
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接

            connection = DriverManager.getConnection(url, "root", "root");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            String sql="insert into user(name,pass) values(?,?)";
            //3.写sql

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setString(1,"王五");
            preparedStatement.setString(2,"123456");
           int  result=preparedStatement.executeUpdate();

           if (result > 0){
               System.out.println("添加成功");
           }else{
               System.out.println("添加失败");
           }
            //5.执行sql

            //6.遍历结果



        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {

                if(preparedStatement != null) {
                    preparedStatement.close();
                }
                if(connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private static void m4() {
        Connection connection = null;
        PreparedStatement preparedStatement = null;


        //jdbc步骤
        //1.加载驱动w
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection = DriverManager.getConnection(url, "root", "root");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            String sql="update user set name = ?, pass= ? where id = ?";
            //3.写sql

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setString(1,"王小明");
            preparedStatement.setString(2,"888");
            preparedStatement.setInt(3,4);
            int  result=preparedStatement.executeUpdate();

            if (result > 0){
                System.out.println("修改成功");
            }else{
                System.out.println("修改失败");
            }
            //5.执行sql

            //6.遍历结果



        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {

                if(preparedStatement != null) {
                    preparedStatement.close();
                }
                if(connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private static void m5() {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
        String user="root";
        String password="root";

        //jdbc步骤
        //1.加载驱动w
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接

            connection = DriverManager.getConnection(url, "root", "root");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            String sql="delete from user where id= ?";
            //3.写sql

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setObject(1,4);

            int  result=preparedStatement.executeUpdate();

            if (result > 0){
                System.out.println("删除成功");
            }else{
                System.out.println("删除失败");
            }
            //5.执行sql

            //6.遍历结果



        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {

                if(preparedStatement != null) {
                    preparedStatement.close();
                }
                if(connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
    }


